The present invention relates to a novel composition for the treatment of Rhus dermatitis associated with exposure to the irritant urushiol oil and other irritating constituents of the sap of the stems, leaves and roots of poison ivy, poison oak, poison sumac and related plants and plant parts. Urushiol oil itself can contain for example 3-alkylcatechols and 3-alkenylcatechols in which the alkyl or alkenyl moieties are generally 15-17 carbons in length, and compounds such as these can be extremely irritating to the skin.
Exposure to urushiol oils can occur in various ways, and the oils are generally exuded to a greater degree by the stems, leaves and roots to the extent that these plant parts are crushed, cut or otherwise disintegrated such as by fire. Downstream smoke from a fire involving urushiol oil-containing plants is a well known cause of severe poison-ivy type dermatitis, and the oils can be carried by boots, shoes, clothes, tools and equipment in ways that can transmit skin irritants even to those who did not come in contact with the originating plant parts. Even though oxidation neutralizes urushiol oils over time, and despite the variability in potency of plants such as these depending on their season of origin, in some cases urushiol oils carried on shoes or other transmission vectors can remain active for years. It is believed that at least fifty percent of the population of the United States is sensitive to the active agents in urushiol oils, and the inflammatory response they stimulate, when brought in contact with the skin, is notorious--and in many cases severe.
Various prior art patents and publications have addressed poison-ivy type dermatitis (Rhus dermatitis) and its treatment. U.S. Pat. No. 3,922,342 discloses the use of a hydrophilic ion exchange material to absorb, upon contact with exposed skin, the phenolic compounds in the urushiol oils to minimize subsequent dermatitis. U.S. Pat. No. 3,875,301 describes a process for treating poison ivy dermatitis with tetraalkyl diamines. U.S. Pat. No. 3,862,331 discloses treating poison oak or ivy with 2-butanone. U.S. Pat. No. 3,749,772 describes a skin coating composition made of film-forming acrylic polymer which forms a barrier against topical exposure to urushiol oils. U.S. Pat. No. 4,259,318 discloses a "poison ivy relief" composition containing p-diphenol oxidase. U.S. Pat. No. 4,389,418 discloses an emollient topical composition which commercially incorporates calamine for the treatment of poison ivy, insect bites, chicken pox rash and etc. U.S. Pat. No. 4,663,151 discloses an aluminum chlorhydrate composition for preventing and/or treating urushiol oil-associated dermatitis. U.S. Pat. No. 5,443,847, discussed further below, discloses detoxification of urushiol with manganese salts.
Naturally-occurring chemicals are also known for treating poison-ivy type dermatitis, see Gibson, M. R. et al., "Activity of Jewelweed and its Enzymes in the Treatment of Rhus Dermatitis," Journal of the American Pharmaceutical Association, pp. 294-296, Gisvold, "The Effect of Some Adsorbents, Precipitants and Oxidants upon the Resin of Rhus Toxicondendron," Journal of the American Pharmaceutical Association, pp. 17-18, and Scarborough, J., ed., Folklore and Folk Medicines, American Institute of the History of Pharmacy, Madison, Wis., 1987. These three articles all address the general applicability of jewelweed extract as an ameliorating agent for Rhus dermatitis, and the latter identifies the utility of plantain extract in this regard also. It should be noted that the Gibson et al. article calls into question the efficacy of jewelweed alone to ameliorate Rhus dermatitis, see page 295, column 2, last full paragraph, as does Scarborough, at the bottom of page 102. U.S. Pat. No. 5,011,689 discloses the use of crushed plants of the genus Plantago, preferably broadleaf Plantain, to form a salve for treating poison ivy. European Patent Application 88116810 discusses an Impatiens capensis (jewelweed) extract for use in treating poison ivy dermatitis.
In general, prior art methods and compositions have not provided a combination therapy in which urushiol oils are neutralized, skin layers are soothed, skin healing is promoted, and dermatitis pain and itching are minimized or eliminated, all from the application of a single specialized topical composition designed to accomplish all these goals. Specifically, poison ivy treatment methods and compositions heretofore have not adequately addressed the need to control inflammation and itching themselves as well as to neutralize the contact dermatitis active agent. As with all contact dermatitis, when the patient scratches the affected skin both the inflammation per se and the active agent exposure itself are exacerbated. A need thus remains for a composition which effectively neutralizes urushiol oils while simultaneously reducing the pain and itch adequately to prevent scratching or rubbing of the affected skin area.